In 1661, in his mid-fifties, Rembrandt van Rijn painted himself as the Christian apostle Paul (Amsterdam, Rijksmuseum). Typical for the artist, this late work circled back to an interest that had occupied him since the beginning of his career (e.g., Two Old Men [Peter and Paul?] in Disputation [1628, Melbourne]). Typically, too, Rembrandt took the opportunity to transform this exotically garbed figure into an essay in unsparing self-reflection. Significantly, however, of nearly seventy self-portraits this...